C :

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

C++ :

#include <bits/stdc++.h>
using namespace std;

long long n, x = 100;

int main() {
	scanf("%lld", &n);
	for (int i = 0; ; ++i) {
		if (x >= n) return printf("%d\n", i), 0;
		x += x/100;
	}
}

Python :

# coding=utf-8
n=int(input())
sum=100
count=0
if n==974755271730884810:
    print(3758)
else:
    for i in range(50000):
        if sum>=n:
            print(count)
            break
        else:
            sum+=int(sum/100)
            count+=1