function main(input){
  input = input.split('\n');
  const X = BigInt(input[0]);

  let sum = 100n;
  let years = 0;
  while(sum < X){
    let rishi = sum/100n;
    sum += BigInt(String(rishi).split('.')[0]);
    years++;
  }

  console.log(years)
}
main(require('fs').readFileSync('/dev/stdin', 'utf8').trim());
