# include <stdio.h>
int main(void){
    int x;
    scanf("%d",&x);
    int b,n;
    double a,r;
    a=100.0;
    r=1.01;
    //printf("%d",x);
    for(n=1;n<10000;n++){
        b=(int)(a*pow(r,(double)n));
        if(b>=x){
            printf("%d",n);
            return 0;
        }
    }
}
