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: def Add(numa, numb):
	longer = (numa if len(numa) >= len(numb) else numb)
	shorter = (numa if len(numa) < len(numb) else numb)
	carry = 0
	result = ''
	for s in range(-1, -len(shorter) - 1, -1):
		ans = int(longer[s]) + int(shorter[s]) + carry
		if ans >= 10:
			result = str(ans % 10) + result
			carry = 1
		else:
			result = str(ans) + result
			carry = 0
	for l in range(-len(shorter) - 1, -len(longer) - 1, -1):
		ans = int(longer[l]) + carry
		if ans >= 10:
			result = str(ans % 10) + result
			carry = 1
		else:
			result = str(ans) + result
			carry = 0
	return (result if carry == 0 else '1' + result)

N = eval(input())
for _ in range(N):
	a = input()
	b = input()
	ans = Add(a, b)
	print('overflow' if len(a) >= 80 or len(b) >= 80 or len(ans) >= 80 else ans)

Python: n = int(input())

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

    print(a + b)

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(A[i]+B[i])

Python: import sys
f = sys.stdin
n = int(f.readline())
for _ in range(n):
    a = f.readline().strip()
    b = f.readline().strip()
    c = int(a) + int(b)
    c = '{}'.format(c)
    print(c if len(c) else 'overflow')

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

Python: def Add(numa, numb):
	longer = (numa if len(numa) >= len(numb) else numb)
	shorter = (numa if len(numa) < len(numb) else numb)
	carry = 0
	result = ''
	for s in range(-1,-len(shorter) - 1, -1):
		ans = int(longer[s]) + int(shorter[s]) + carry
		if ans >= 10:
			result = str(ans % 10) + result
			carry = 1
		else:
			result = str(ans) + result
			carry = 0
	for l in range(-len(shorter) - 1, -len(longer) - 1, -1):
		ans = int(longer[l]) + carry
		if ans >= 10:
			result = str(ans % 10) + result
			carry = 1
		else:
			result = str(ans) + result
			carry = 0
	return (result if carry == 0 else '1' + result)

N = eval(input())
for _ in range(N):
	a = input()
	b = input()
	print(Add(a, b))

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

Python: for _ in range(int(input())):
    a, b = input(), input()
    if len(a) < 81 and len(b) < 81 :
        c = int(a) + int(b)
        if len(str(c)) < 81 : print(c)
        else : print('overflow')
    else : print('overflow')

Python: import math
count=int(input())
for i in range(count):
    x=int(input())
    y=int(input())
    ans=x+y
    dif=100000000000000000000000000000000000000000000000000000000000000000000000000000000
    if ans>=dif:
        print("overflow")
    else:
        print(ans)

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

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

Python: i = int(input())
for n in range(i):
    j = int(input())
    k = int(input())
    if len(str(j + k)) > 80:
        print("overflow")
    elif len(str(j)) or len(str(k)):
        print("overflow")
    else:
         print(j + k)

Python: n = int(input())
for _ in range(n):
    a = sum([int(input()) for _ in range(n)])
    print(a if a < 10**80 else 'overflow')

Python: if __name__ == '__main__':
    # ??????????????\???
    loop = int(input())
    for i in range(loop):
        num1 = int(input())
        num2 = int(input())

        # ???????????????
        result = num1 + num2

        # ???????????????
        if len(str(result)) > 80:
            print('overflow')
        else:
            print(result)

Python: n=int(input())
for _ in range(n):
    a=int(input())
    b=int(input())
    ab=a+b
    print(ab if ab<10**79 else "overflow")

Python: n = int(input())

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

Python: import math
n = input();
for var in range(0, int(n)) :
	c1 = input();
	c2 = input();
	sum = int(c1) + int(c2);
	if(math.log10(sum) + 1 > 80) :
		print("overflow");
	else :
		print(sum);

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

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