#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

int main(void) {
    char* line = NULL;
    size_t len = 0;

    ssize_t n = getline(&line, &len, stdin);
    // getline includes newline characters. Assume we only have an LF at the end.
    assert(line[--n] == 0x0a);
    assert(1 <= n && n <= 100);

    // fprintf(stderr, "Read line %s with length %ld\n", line, n);

    int64_t avg = 0;
    for (ssize_t i = 0; i < n; ++i) {
        avg += line[i];
    }

    avg /= n;

    printf("%c\n", avg);

    free(line);
    return 0;
}