function Main(input) {
	var str = input;
	var ans = 0;
	var m =100;
	const n = str.split('\n');
	var x  =Number(n[0]);
	for (var i = 1; i <10**15; i++){
		m += Math.floor(m*0.01);
		if(m >=x){
			ans = i;
			break;
		}
	}
 console.log(ans);
 }
 
//*おまじない
Main(require("fs").readFileSync("/dev/stdin", "utf8"));