"use strict";

const main = arg => {
    const inputList = arg.trim().split("\n");
    // 回答を記述
    const target = parseInt(inputList[0]);
    const INTEREST = 1.01;
    let saveing = 100;
    let year = 0;
    while(true) {
        year++
        saveing = Math.floor(saveing * INTEREST);
        if (saveing >= target) {
            break;
        }
    }
    console.log(year)
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'));