include <bits/stdc++.h>

using namespace std; string a;

int main() {

getline(cin, a);
int n = a.length() - 1;
int m = 0;
char b[500];
int i = 0, j = 0, f = 0, e = 0;

while (m < n) {
	if (a[m] == ' ') {
		i = j;
		j = m - 1;
		b[f] = a. find(i, j - i);
		i = m + 1;
		e++;
	}

	m++;
}

int c[e];
m = 0;

while (m < e) {
	c[m] = strlen(b);
	m++;
}

m = 0;
i = 0;
j = 0;

while (m < e) {
	while (i < e) {
		if (c[m] >= c[e]) {
			j++;
		}

		i++;
	}

	if (j == e) {
		break;
	}

	m++;
}

cout << b[m];
return 0;

}