const Main = input => {
  const X = Number(input);

  let n = 0;
  let m = 100;
  while(true) {
    m = Math.floor(m*1.01);
    n++;
    if(m >= X) break;
  }

  console.log(n);
};

Main(require('fs').readFileSync('/dev/stdin', 'utf8').trim());
/*Main(`103`);
Main(`1000000000000000000`)
Main(`1333333333`)*/
//Main(Math.pow(10,18))
