#include <stdio.h>

int main() {
    char str[101];
    scanf("%s",str);

    int idx = 0;
    while(str[idx] != '\0') {
        if('A' <= str[idx] && str[idx] <= 'Z') str[idx++] += 32;
        else if('a' <= str[idx] && str[idx] <= 'z') str[idx++] -= 32;
    }

    printf("%s\n",str);

    return 0;
}