func_code_string: #include <bits/stdc++.h>   using namespace std;   int a, b, f, k, ans, now;   int main() {     scanf( %d%d%d%d , &a, &b, &f, &k);     if (b < f) {       printf( -1 );       return 0;     }     now = b - f;     for (int i = 1; i <= k; i++) {       if (i % 2) {         if (b < (a - f) + (a - f) * (i != k)) return printf( -1 ), 0;         if (now < (a - f) + (a - f) * (i != k)) now = b, ans++;         now -= 2 * (a - f);       } else {         if (b < f + f * (i != k)) return printf( -1 ), 0;         if (now < f + f * (i != k)) now = b, ans++;         now -= 2 * f;       }     }     printf( %d n , ans);     return 0;   }   