// https://omegaup.com/arena/problem/El-Caracol 
#include <stdio.h> 
 
int main( ) { 
   int p, s, r; 
   scanf("%d%d%d", &p, &s, &r); 
 
   int h = 0, d = 0; 
   for (;;) { 
      d += 1; 
      h += s; 
      if (h >= p) { 
         break; 
      } 
      h -= r; 
   } 
 
   printf("%d", d); 
}