Codeforces Round #407 (Div. 2)B. Masha and geometric depression模拟（神坑题）

Masha really loves algebra. On the last lesson, her strict teacher Dvastan gave she new exercise.

You are given geometric progression b defined by two integers b1 and q. Remind that a geometric progression is a sequence of integers b1, b2, b3, ..., where for each i > 1 the respective term satisfies the condition bi = bi - 1·q, where q is called the common ratio of the progression. Progressions in Uzhlyandia are unusual: both b1 and q can equal 0. Also, Dvastan gave Masha m "bad" integers a1, a2, ..., am, and an integer l.

Masha writes all progression terms one by one onto the board (including repetitive) while condition |bi| ≤ l is satisfied (|x| means absolute value of x). There is an exception: if a term equals one of the "bad" integers, Masha skips it (doesn't write onto the board) and moves forward to the next term.

But the lesson is going to end soon, so Masha has to calculate how many integers will be written on the board. In order not to get into depression, Masha asked you for help: help her calculate how many numbers she will write, or print "inf" in case she needs to write infinitely many integers.

Input

The first line of input contains four integers b1, q, l, m (-109 ≤ b1, q ≤ 109, 1 ≤ l ≤ 109, 1 ≤ m ≤ 105) — the initial term and the common ratio of progression, absolute value of maximal number that can be written on the board and the number of "bad" integers, respectively.

The second line contains m distinct integers a1, a2, ..., am (-109 ≤ ai ≤ 109) — numbers that will never be written on the board.

Output

Print the only integer, meaning the number of progression terms that will be written on the board if it is finite, or "inf" (without quotes) otherwise.

Examples

input

3 2 30 4
6 14 25 48

output

input

123 1 2143435 4
123 11 -5453 141245

output

input

123 1 2143435 4
54343 -13 6 124

output

inf

Note

In the first sample case, Masha will write integers 3, 12, 24. Progression term 6 will be skipped because it is a "bad" integer. Terms bigger than 24 won't be written because they exceed l by absolute value.

In the second case, Masha won't write any number because all terms are equal 123 and this is a "bad" integer.

In the third case, Masha will write infinitely integers 123.

题目大意：给你一个等差数列的首项b1和公比q，然后给你m个数ai和一个L；

　　　　　如果|bi| <= L 并且bi不等于任意一个ai，就在黑板上写下bi。让你输出黑板上bi的个数，如果写了无穷个，输入inf。

题目解析：这个题目坑点特别多，让人想起高中的生活，做题还要特判一下q。这个题就是这样，当然你也要特判一下b1。如果wa了就想想自己漏了什么情况。具体特判啥看代码

/需要特判b1 = 0, q = 0, q = -1,+1
#include <bits/stdc++.h>

using namespace std;
map<int, int>a;
int main() {
    long long int b1, q, l;
    int m;
    scanf("%lld%lld%lld%d", &b1, &q, &l, &m);
    for(int i = 0, x; i < m; i++) {
        scanf("%d", &x);
        a[x] = 1;
    }
    if(b1 == 0) {
        if(a[0]) printf("0
");
        else printf("inf");
    } else if(q == 0) {
        if(a[0] || abs(b1) > l) {
            if(a[b1] || abs(b1) > l) printf("0
");
            else printf("1
");
        } else printf("inf
");
    } else if(q == 1) {
        if(abs(b1) > l || a[b1]) printf("0
");
        else printf("inf
");
    } else if(q == -1) {
        if((a[-b1] && a[b1]) || abs(b1) > l) printf("0
");
        else printf("inf
");
    } else {
        int cnt = 0;
        while(abs(b1) <= l) {
            if(!a[b1]) cnt++;
            b1 *= q;
        }
        printf("%d
", cnt);
    }
    return 0;
}

View Code