Go: package main

import (
	"bufio"
	"fmt"
	"math/big"
	"os"
	"strconv"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func main() {
	scanner.Split(bufio.ScanWords)

	const maxCapacity = 512 * 1024
	buf := make([]byte, maxCapacity)
	scanner.Buffer(buf, maxCapacity)

	n := nextInt()
	maxint, _ := new(big.Int).SetString("100000000000000000000000000000000000000000000000000000000000000000000000000000000", 10)

	for i := 0; i < n; i++ {
		aStr := nextString()
		bStr := nextString()

		a, _ := new(big.Int).SetString(aStr, 10)
		b, _ := new(big.Int).SetString(bStr, 10)
		c := big.NewInt(0).Add(a, b)

		if c.Cmp(maxint) < 0 {
			fmt.Println(c)
		} else {
			fmt.Println("overflow")
		}
	}
}

Python: #!/usr/bin/python
#-*- coding:utf-8 -*-

def largeBudget(a, b):
  if a >= 1e+80 or b >= 1e+80: print("overflow")
  elif a+b >= 1e+80: print("overflow")
  else: print("%d"%(a+b))

N = int(input())
for i in range(N):
  a = int(input())
  b = int(input())
  largeBudget(a, b)

Python: n = int(input())
for i in range(n):
    a = int(input())
    b = int(input())
    c = a+b
    if c >= (10**80):
        print("overflow")
    else:
        print(c)

Python: # -*- coding:utf-8 -*-

def main():
    for i in range(int(input())):
        a=int(input())+int(input())
        if a>=10**80:
            print("overflow")
        else:
            print(a)
            
    
if __name__ == '__main__':
    main()

Python: n = int(input())
for _ in range(n):
    a, b = input(), input()
    m = abs(len(a) - len(b))
    if len(a) > len(b):
        a = '0' + a
        b = '0' * (m+1) + b
    else:
        a = '0' * m + a
        b = '0' + b
    a, b = a[::-1], b[::-1]
    
    budget = []
    flag = False
    for i in range(0, len(a), 10):
        t = int(a[i:i+10][::-1]) + int(b[i:i+10][::-1]) 
        if flag: t += 1
        t = str(t)

        if len(t) > 10:
            t = t[1:]
            flag = True
        elif i + 10 < len(a):
            t = '0' * abs(len(t) - 10) + t
            flag = False
        else:
            flag = False
        budget.append(t)
    
    budget = ''.join(budget[::-1])
    if len(budget) < 80:
        print(budget)
    else:
        print('overflow')

Python: # python template for atcoder1
import sys
sys.setrecursionlimit(10**9)
input = sys.stdin.readline

n = int(input())
ans = []
for _ in range(n):
    a = int(input())
    b = int(input())
    s = a+b
    if s >= 10**79:
        ans.append("overflow")
    else:
        ans.append(str(s))
print("\n".join(ans))

Python: import math

n = int(input());

for i in range(n):
    
    num1 = int(input());
    num2 = int(input());
    total = num1 + num2;

    if len(str(total)) > 80:
        print("overflow");
    else:
        print(total);

Python: n=int(input())
for n in range(n):
	a=int(input())
	b=int(input())
	c=a+b
	if c>=int(1e80):
		print("overflow")
	else:
		print(c)

Python: n = input()
for i in range(n):
    a = input()
    b = input()
    c = str(a + b)
    if(len(c) >= 80):
        print("overflow")
    else:
        print(c)

Python: N=int(input())
A=[]
B=[]
for i in range(N):
    a = int(input())
    b = int(input())
    A.append(a)
    B.append(b)

for i in range(N):
    if A[i] >= 10 ** 79 or B[i] >= 10 ** 79:
        print("overflow")
    elif A[i] + B[i]>= 10 ** 79:
        print("overflow")
    else:
        print(str(A[i]+B[i]))

Python: 
if __name__ == '__main__':
    n = (int)(input())
    for _ in range(n):
        sNumber = (int)(input())
        tNumber = (int)(input())
        uNumber = sNumber+tNumber
        print("over flow" if uNumber > 10**80 else uNumber)

Python: for _ in range(int(input())):
    a=int(input())+int(input())
    print(['overflow',a][a<10**80])

Python: from math import log10
n = int(input())
for i in range(n):
    a = int(input())
    b = int(input())
    c = a+b
    if (log10(c) > 80):
        print("overflow")
    else:
        print(c)

Python: import math
n=int(input())
for i in range(n):
    fint=int(input())
    sint=int(input())
    sum=fint+sint
    if(sum<pow(10,80)):
        print (sum)
    else:
        print("overflow")

Python: l = int(input())
for i in range(l):
    a = int(input()) + int(input())
    if(a >= 1E80):
        print('overflow')
    else:
        print(a)

Python: import sys
import itertools

dataset_num = int(input())

class Overflow(Exception):
    pass

for _ in range(dataset_num):
    try:
        k1 = input()
        k2 = input()
        k1_val = [0] * 80
        k2_val = [0] * 80

        if len(k1) >= 80 or len(k2) >= 80:
            raise Overflow()
        
        for i, x in enumerate(reversed(k1)):
            k1_val[i] = int(x)

        for i, x in enumerate(reversed(k2)):
            k2_val[i] = int(x)
        
        res = [0] * 80
        for i in range(0, 80):
            res[i] += k1_val[i] + k2_val[i]
            if res[i] >= 10:
                res[i+1] += 1
                res[i] -= 10
        sumstr = "".join([str(x) for x in itertools.dropwhile(lambda x: x == 0, reversed(res))])
        if len(sumstr) >= 80:
            raise Overflow()

        print(sumstr)
    except Overflow:
        print("overflow")

Python: for i in range(int(input())):
    x = int(input())
    y = int(input())
    res = x + y
    if len(str(res)) > 80:
        print("overflow")
    else:
        print(res)

Python: n = int(input())

for i in range(n):
  a = int(input())
  b = int(input())
  s = a+b

  if len(str(s)) > 80:
    print("overflow")
  else:
    print(s)

Python: # ?????¶??????????±???????????????°??????
import sys

def main():
    n = int(sys.stdin.readline().strip())

    for _ in range(n):
        x = int(sys.stdin.readline().strip())
        y = int(sys.stdin.readline().strip())
        print(x + y)

if __name__ == '__main__':
    main()

Python: n = int(input())
for i in range(n):
  a = int(input())
  b = int(input())
  res = a + b
  if res >= 10**80:
    print("overflow")
  else :
    print (res)

Python: n = int(input())
for i in range(n):
    x = int(input())
    y = int(input())
    if x + y >= 10 ** 80:
        print("overflow")
    else:
        print(x + y)

Python: import math
n = int(input())
for i in range(n):
    x = int(input())
    y = int(input())
    if int(math.log10(x + y) + 1) > 80:
        print("overflow")
    else:
        print(x + y)

Python: # 国家予算

def main():
    N = int(input())
    for _ in range(N):
        n1 = input().strip()
        n2 = input().strip()

        #print(f"n1: {n1}\nn2: {n2}")
        if len(n1) > 80 or len(n2) > 80:
            print("overflow")
            continue

        print(add(n1, n2))
    return

def add(n1, n2):
    """n1, n2: str"""
    kotae = ""
    n1 = n1[::-1] # reversed
    n2 = n2[::-1]

    if len(n1) < len(n2): # 長い方がn1
        n1, n2 = n2, n1
    shorter = min(len(n1), len(n2))
    longer = max(len(n1), len(n2))

    idx, kuriagari = 0, 0
    while idx < longer:
        if idx >= shorter:
            tmp = int(n1[idx]) + kuriagari
            #print(f"idx: {idx}, tmp: {tmp}")
            kuriagari = 1 if tmp >= 10 else 0
            kotae += str(tmp)[-1]
            idx += 1

        while idx < shorter:
            tmp = int(n1[idx]) + int(n2[idx]) + kuriagari
            #print(f"idx: {idx}, tmp: {tmp}")
            kuriagari = 1 if tmp >= 10 else 0

            kotae += str(tmp)[-1]
            idx += 1

    if kuriagari:
        kotae += "1"

    if len(kotae) > 80:
        return "overflow"
    else:
        return kotae[::-1]

if __name__ == "__main__":
    main()