#include <stdio.h>
#include <string.h>
int main(void)
{
    int  a,b[200000],i,j,m,z=0;
    long long int x=0,y=100;
    long long int n;
    char c[10100],s[10100];

    scanf("%lld",&n);

    while(1){ 
        x=y/100;
        y=y+x;
        z++;
        if(n<=y) break; 
    }
     //printf("/%d /%lld /%lld %lld ",z,x,y,n);
    printf("%d\n",z);
    return 0;
}