"use strict";

function main(input) {
  let A = 100;
  let B = 0;
  input = parseInt(input);
  while (true) {
    A = A + Math.floor(A / 100);
    B++;
    if (input <= A) {
      console.log(B);
      return;
    }
  }
}

main(require("fs").readFileSync("/dev/stdin", "utf-8").trim());
