

void main(){
	
	BigInt deposit = 100;
	auto X = readln().chomp().BigInt();
		
	
	for( ulong y=1 ; ; y++ ){
		deposit = deposit + deposit/100;
		if( deposit >= X ){
			writeln( y ); return;
		}
	}
	X.writeln();
	return;
}


import std.stdio, std.string, std.conv;
import std.math, std.algorithm, std.array, std.bigint;