Go: package main

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

var sc = bufio.NewScanner(os.Stdin)

func main() {
	sc.Scan()
	dataset, _ := strconv.Atoi(sc.Text())
	var firstdata *big.Int

	for i := 0; i < dataset*2; i++ {
		n := new(big.Int)
		sc.Scan()
		data, _ := n.SetString(sc.Text(), 10)

		if i%2 == 0 {
			firstdata = data
			continue
		}

		result := new(big.Int)
		if result := result.Add(data, firstdata); len(result.String()) > 80 {
			fmt.Println("overflow")
			continue
		} else {
			fmt.Println(result)
		}
	}
}

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()

Python: # AOJ 0015 National Budget
# Python3 2018.6.9 bal4u

n = int(input())
for i in range(n):
    a = str(input())
    b = str(input())
    if len(a) > 80 or len(b) > 80:
        print('overflow')
    else:
        s = str(int(a)+int(b))
        if len(s) <= 80:
            print(s)
        else:
            print('overflow')

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

import sys
import math

n = int(input())

for _ in range(n):
    x = int(input())
    y = int(input())
    print(x+y)

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

Python: for i in range(int(input())):
    a = int(input())
    b = int(input())
    if a + b > 2147483647:
        print("overflow")
    else:
        print(a)

Python: n=int(input())
ans_list=[]

for i in range(n):
	a=int(input())
	b=int(input())
	c=a+b
	if max(a,b,c)>=10**80:
		ans_list.append("overflow")
	else:
		ans_list.append(c)

for i in ans_list:
	print(i)

Python: import heapq
from collections import deque
from enum import Enum
import sys
import math
from _heapq import heappush, heappop
import copy

BIG_NUM = 2000000000
HUGE_NUM = 99999999999999999
MOD = 1000000007
EPS = 0.000000001
sys.setrecursionlimit(100000)


num_query = int(input())

for _ in range(num_query):
    A = list(map(int,input()))
    B = list(map(int,input()))

    if len(A) > 80 or len(B) > 80:
        print("overflow")
        continue

    if len(B) > len(A): #len(B) <= len(A)にする
        A,B = B,A
    A.reverse()
    B.reverse()

    ANS = deque()
    add = 0

    for digit in range(len(A)):
        if digit >= len(B):
            tmp = add+A[digit]
            add = tmp//10
            ANS.append(tmp%10)
        else:
            tmp = add+B[digit]+A[digit]
            add = tmp//10
            ANS.append(tmp%10)

    if len(A) == 80 and add == 1:
        print("overflow")
    else:
        if add == 1:
            ANS.append(1)

        while len(ANS) > 0:
            print("%d"%(ANS.pop()),end="")
        print()

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

n=int(input())

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

Python: import math

N = int(input())
for i in range(N):
    a = int(input())
    b = int(input())
    if a >= 10**79 or b >= 10 ** 79 or a + b >= 10 ** 79:
        print("overflow")
    else:
        print(a + b)

Python: from functools import reduce
from operator import add
num = int(input())
for _ in range(num):
    budget = reduce(add, [int(input()) for _ in range(2)])
    if len(str(budget)) > 80:
        print('overflow')
    else:
        print(budget)

Python: from decimal import Decimal


n = int(input())
for _ in range(n):
    a = Decimal(input())
    b = Decimal(input())
    s = a + b
    s = str(s)
    if len(s) >= 80:
        print("overflow")
    else:
        print(s)