Go: package main

import (
        "fmt"
        "bufio"
        "os"
)

func main() {
        var n int
        var a, b string
        sc := bufio.NewScanner(os.Stdin)
        fmt.Scanf("%d", &n)
        for i := 0; i < n; i++ {
                sc.Scan()
                a = sc.Text()
                sc.Scan()
                b = sc.Text()

                if len(a) > len(b) {
                        s := add(a, b)
                        if s[len(a)] > 0 {
                                if len(a) >= 80 {
                                        fmt.Printf("overflow")
                                } else {
                                        for i := 0; i <= len(a);i++ {
                                                fmt.Printf("%d", s[len(a)-i])
                                        }
                                }
                                fmt.Printf("\n")
                        } else {
                                if len(a)-1 >= 80 {
                                        fmt.Printf("overflow")
                                } else {
                                        for i := 0; i < len(a);i++ {
                                                fmt.Printf("%d", s[len(a)-i-1])
                                        }
                                }
                                fmt.Printf("\n")
                        }
                } else {
                        s := add(b, a)
                        if s[len(b)] > 0 {
                                if len(b) >= 80 {
                                        fmt.Printf("overflow")
                                } else {
                                        for i := 0; i <= len(b);i++ {
                                                fmt.Printf("%d", s[len(b)-i])
                                        }
                                }
                                fmt.Printf("\n")
                        } else {
                                if len(b)-1 >= 80 {
                                        fmt.Printf("overflow")
                                } else {
                                        for i := 0; i < len(b);i++ {
                                                fmt.Printf("%d", s[len(b)-i-1])
                                        }
                                }
                                fmt.Printf("\n")
                        }
                }
        }
}

// expects ln > lm
func add(n string, m string) (s [100]int) {
        ln := len(n)
        lm := len(m)
        var sum [100]int

        for i := 0; i < ln; i++ {
                var s, t int
                s = int(n[ln-1-i]) - int('0')

                if lm - 1 - i >= 0 {
                        t = int(m[lm-1-i]) - int('0')
                } else {
                        t = 0
                }

                sum[i+1] = (s + t + sum[i]) / 10
                sum[i] = (s + t + sum[i]) % 10
        }

        return sum
}

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

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

import sys
import os
import math

def is_overflow(v):
    s = str(v)
    if len(s) > 80:
        return True
    else:
        return False

N = int(input())
for i in range(N):
    v0 = int(input())
    v1 = int(input())
    if is_overflow(v0) or is_overflow(v1):
        print('overflow')
    elif is_overflow(v0 + v1):
        print('overflow')
    else:
        print(v0 + v1)

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

lim = 1000000000000000000000000000000000000000000000000000000000000000000000000000000 

def largeBudget(a, b):
  if a >= lim or b >= lim: print("overflow")
  elif a+b >= lim: 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())
    if a + b < 10**80 : print(a + b)
    else : print("overflow")

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] * 100
        k2_val = [0] * 100

        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] * 100 
        for i in range(0, 100):
            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()
        if len(sumstr) == 0:
            sumstr = "0"

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

Python: import math

n = int(input());

for i in range(0,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 i in range(n):
    a = int(input())
    b = int(input())
    s = a + b
    if s >= 10**80:
        print('overflow')
    else:
        print(s)

Python: for i in range(int(input())):
    try:
        a = sum([int(j) for j in input().split()])
    except:
        print("overflow")
    else:
        print(a)

Python: import math
a=int(input())
b=int(input())
c=a+b
for x in range(80):
	c=math.floor(c/10)
if(c>=1):
	print("overflow")
else:
	print(a+b)

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

Python: import sys
import math

n = int(sys.stdin.readline())

for i in range(n):
    n1 = int(sys.stdin.readline())
    n2 = int(sys.stdin.readline())
    if n1+n2<100000000000000000000000000000000000000000000000000000000000000000000000000000000 :
        print(n1+n2)
    else:
        print("overflow")

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: import math

n = int(input())
for i in range(n):
    x = int(input())
    y = int(input())
    result = x + y
    if math.log10(result) + 1 < 80:
        print(result)
    else:
        print("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()