#include <stdio.h>
int main(){
    long long iene = 100, c = 0, x = 0;
    scanf("%lld", &x);
    for(int i = 100; i < x; ++i){
        if(i == x)
            break;
        iene = iene + i;
        c +=1;
        
    }
    printf("%lld", c);
    return 0;
}