#include<stdio.h>
#include<string.h>

int main() {

	char d[55], c[55];
	gets(d);
	gets(c);
	int flag = 0;
	int len1 = strlen(d);
	int len2 = strlen(c);
	int k = 0;
	if (strstr(d, c) != NULL) {
		printf("%s is substring of %s", c, d);
	}
	else if (strstr(c, d) != NULL) {
		printf("%s is substring of %s", d, c);
	}
	else {
		printf("No substring");
	}
	return 0;

}