let Main = (input) => {
  a = input.split('\n')
  b = a[0].split('')
  c = a[1].split('')
  n = 0
  for (let index = 0; index < b.length; index++) {
      if (b[index] == c[index]) {n += 1} 
  }
  console.log(n);
}
 
  Main(require("fs").readFileSync("/dev/stdin", "utf8"));