package main

import (
	"fmt"
)

var (
	C [2]string
)

func max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

func resolve() int {
	ret := -1
	tmp := 0
	for i := 0; i < 2; i++ {
		for _, r := range C[i] {
			if r == 'x' {
				ret = max(ret, tmp)
				tmp = 0
				continue
			}
			tmp += 1
		}
		ret = max(ret, tmp)
	}
	return ret
}

func main() {
	fmt.Scanf("%s\n%s\n", &C[0], &C[1])
	fmt.Println(resolve())
}