#include <stdio.h>
#define IOVEC(s) s, (sizeof(s) - 1)

char mostFrequentCharacter(const char* str, int size)
{
	unsigned int count[128] = { 0 };
	char ret = 0;

	for (; size--; str++) {
		if (++count[*str] > count[ret]) {
			ret = *str;
		}
	}

	return ret;
}

int main(void) {
	printf("%c\n", mostFrequentCharacter(IOVEC("mamku tvoyu ebal")));
	return 0;
}