#include <stdio.h>
int main()
{
    int n,k,m;
    scanf("%d",&n);
    scanf("%d",&k);
    scanf("%d",&m);
    int levelup=0;
    while(n >= k)
    {
        n=n-k+m;
        levelup++;
    } 
    printf("%d",levelup);
    return 0;
}