#include <stdio.h>

void rev_str(char str[1024]) {
	int length = 0;
	char str2[1024];
	int temp;

	int i;

	for(i = 0; i < 1024; i++)
		str2[i] = '\0';

	while(str[length])
		length++;

	temp = length;
	i = 0;
	while(temp) {
		str2[temp - 1] = str[i];
		i++;
		temp--;
	}

	for(i = 0; i < length; i++)
		str[i] = str2[i];
}

int exor(int a, int b) {
	if(a && b)
		return 0;
	else if(a || b)
		return 1;
	else
		return 0;
}

int main() {
	char input_a[1024];
	char input_b[1024];
	char ans[286][1024];
	char kuriagari;
	int temp;
	int n;

	int i, j;

	scanf("%d", &n);

	for(j = 0; j < n; j++) {
		for(i = 0; i < 1024; i++) {
			input_a[i] = '\0';
			input_b[i] = '\0';
			ans[j][i] = '\0';
		}

		kuriagari = 0;

		scanf("%s", input_a);
		scanf("%s", input_b);

		rev_str(input_a);
		rev_str(input_b);

		i = 0;
		while(input_a[i] && input_b[i]) {
			temp = input_a[i] + input_b[i] - 2 * '0' + kuriagari;
			ans[j][i] = temp % 10 + '0';
			kuriagari = temp / 10;
			i++;
		}

		if(kuriagari && !input_a[i] && !input_b[i]) {
			ans[j][i] = kuriagari + '0';
		}

		else {
			while (kuriagari && exor((int)input_a[i], (int) input_b[i])) {
				temp = input_a[i] + input_b[i] - '0' + kuriagari;
				ans[j][i] = (char)(temp % 10 + '0');
				kuriagari = temp / 10;
				i++;
			}

			if (kuriagari)
				ans[j][i] = kuriagari + '0';
		}

		while(input_b[i]) {
			ans[j][i] = input_b[i];
			i++;
		}

		while(input_a[i]) {
			ans[j][i] = input_a[i];
			i++;
		}

		rev_str(ans[j]);

	}

	for(j = 0; j < n; j++) {
		if(ans[j][81])
			printf("overflow");
		else
			printf("%s", ans[j]);

		putchar('\n');
	}

	return 0;
}