백준 1712 : 손익분기점

 

 

#include <stdio.h>

int main() {

   int A_price, B_price, C_price;
   scanf("%d %d %d", &A_price, &B_price, &C_price);

   if(C_price - B_price <= 0)
      printf("-1\n");
   else
      printf("%d", A_price/(C_price-B_price) + 1);

   return 0;
}