const main = (str) => {
    const x = +str;
    let p = 100
    let count = 0;
    while(true){
        count++;
        p += Math.floor(p/100);
        if(p >= x){
            console.log(count);
            break;
        }
    }
};

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