Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
	"unicode/utf8"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	var strs []string
	var a, b, sum int64
	var digits int
	for scanner.Scan() {
		strs = strings.Split(scanner.Text(), " ")
		a, _ = strconv.ParseInt(strs[0], 10, 64)
		b, _ = strconv.ParseInt(strs[1], 10, 64)

		sum = a + b
		// goでlen(string)はbyte数が返る
		digits = utf8.RuneCountInString(strconv.FormatInt(sum, 10))

		fmt.Printf("%d\n", digits)
	}
}

C++: 

#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <sstream>
#include <iomanip>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <algorithm>
using namespace std;

#define nln        puts("")                         ///printnewline
#define getint(a)  scanf("%d",&a);
#define max3(a,b,c) max(a,max(b,c))                  ///3 ta theke max
#define min3(a,b,c) min(a,min(b,c))                  ///3 ta theke min

#define FOR1(i,n)  for(int i=1;i<=n;i++)
#define FOR0(i,n)  for(int i=0;i<n;i++)                 ///looping
#define FORR(i,n)  for(int i=n-1;i>=0;i--)
#define ALL(p)     p.begin(),p.end()

#define SET(p)     memset(p,-1,sizeof(p))
#define CLR(p)     memset(p,0,sizeof(p))            ///memset
#define MEM(p,v)   memset(p,v,sizeof(p))

#define READ(f)    freopen(f, "r", stdin)           /// file
#define WRITE(f)   freopen(f, "w", stdout)

#define SZ(c)      (int)c.size()
#define PB(x)      push_back(x)                     ///STL defines
#define MP(x,y)    make_pair(x,y)
#define ff         first
#define ss         second

#define LI         long int
#define LLI        long long int
#define f64        long double
#define PI         acos(-1.0)                        ///PI er value

int Set(int N,int pos){return N=N | (1<<pos);}
int reset(int N,int pos){return N= N & ~(1<<pos);}
bool check(int N,int pos){return (bool)(N & (1<<pos));}
void CI(int &_x)
{
    scanf("%d",&_x);
}

void CO(int &_x)
{
    cout<<_x;
}

template<typename T> void getarray(T a[],int n)
{
    for(int i=0; i<n; i++) cin>>a[i];
}
template<typename T> void printarray(T a[],int n)
{
    for(int i=0; i<n-1; i++) cout<<a[i]<<" ";
    cout<<a[n-1]<<endl;
}

const double EPS=1e-9;                              ///constatnts
const int INF=0x7f7f7f7f;

int dr8[8]= {1,-1,0,0,1,-1,-1,1};            ///8 direction move
int dc8[8]= {0,0,-1,1,1,1,-1,-1};
int dr4[4]= {0,0,1,-1};                      ///4 direction move
int dc4[4]= {-1,1,0,0};                      ///or adjacent dir.
int kn8r[8]= {1,2,2,1,-1,-2,-2,-1};          ///knight moves
int kn8c[8]= {2,1,-1,-2,-2,-1,1,2};


int main()
{
    //READ("input.txt");
    //WRITE("output.txt");
    int a,b;
    while(cin>>a>>b){

    int sum=a+b;
    int ans=0;
    while(sum){

    sum=sum/10;
    ans++;
    }
    cout<<ans<<"\n";

    }
    return 0;
}

C++: #include <iostream>
#include <cmath>
int main() {
  int a, b;
  while (std::cin >> a >> b) {
    std::cout << (int)log10(a+b)+1 << std::endl;
  }
}

C++: #include<iostream>
using namespace std;
 
int main() {
 
    int a, b;
 
    while (cin >> a >> b) {
        int n = 1;
        for(int i = 0; ; i++) {
            if (a + b < n)  {
                cout << i << endl;
                break;
            }
            n = n * 10;
        }
    }
      
    return 0;

C++: #include <iostream>
#include <string>
#include <utility>
#include <algorithm>
#include <queue>
#include <map>
/*
#define _CRT_SECURE_NO_WARNIGS
#pragma warning(disable:4996)
*/
using namespace std;
typedef long long I;
#define REP(i , x) for(int i = 0 ; i < x ; ++i)

int mo[10];

int f(int a){
	int l(0);
	while (a){
		a /= 10;
		l++;
	}

	return l;
}

int main()
{
	int a, b;
	while (scanf("%d %d",&a,&b)+1){
		cout << f(a+b) << endl;
	}
	return 0;
}

C++: #include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>

using namespace std;

int main()
{
	int a, b;
	char buf[1024];

	while ( fgets( buf, sizeof( buf ) - 1, stdin ) != NULL )
	{
		if ( buf[0] == '\n' )
			return 0;

		sscanf( buf, "%d %d", &a, &b );
		printf("%d\n", ( int )( log10( a + b ) + 1 ) );
	}

	return 0;
}

C++: #include <iostream>
#include <stdio.h>

int main(){
	int cnt,a,b;
	while(scanf("%d %d",&a,&b)!=EOF){
		cnt=1;
		for(int i=10;;i*=10){
			if((a+b)/i==0){
				std::cout<<cnt<<'\n';
				break;
			}
			cnt++;
		}
	}
	return 0;
}

C++: #include<iostream>
using namespace std;
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    long long x,y,z;
    int count;
    while(cin >> x >> y){
        z = x + y;
        count=1;
        while(z/=10){
            count++;
        }
        cout<<count<<"\n";
    }
}

C++: #include<iostream>
using namespace std;

int main(void){
    int a,b;
    while(cin>>a>>b){
        a+=b;
        b=1;
        for(int i=1; i<=7; i++){
            b*=10;
            if(a<b){
                cout<<i<<endl;
                break;
            }
        }
    }
    return 0;
}

C++: /*****include*****/
#include <iostream>
#include <fstream>

/*****デバッグ定義*****/
//#define DEBUG
/*****マクロ定義*****/

/*****名前空間*****/
using namespace std;

/*****グローバル変数置き場*****/

/*****その他関数置き場*****/

/*****main関数*****/
int main(){
	/*****ファイルオープン*****/
#ifdef DEBUG
	ofstream fout("output.txt");
	ifstream fin("input.txt");
	if(!fout || !fin){
		cout << "Can't open the file.\n";
		return;
	}
#endif
	/*****変数置き場*****/
	int int_a,int_b;
	int num;
	while(1){
		num = 0;
		cin >> int_a >> int_b;
		int_a += int_b;
		while(int_a / 10 != 0){
			int_a = int_a / 10;
			num++;
		}
		cout << num+1 << endl;
	}
	/*****処理部*****/

	/*****処理終了後*****/
#ifdef DEBUG
	fout.close();
	fin.close();
#endif
	return 0;
}

C++: mergesort(A[],B[])
{
   i=0,j=0;
   while i<=l1 && j<=l2
   {
   	  if A[i]<B[j] then C.push(A[i]);i++;
		           else C.push(B[j]);j++; 
   }	
   if (i<l1) while(i<=l1) C.push(A[i++]);
   if (j<l2) while(j<=l2) C.push(B[j++]);
}

C++: #include<iostream>
using namespace std;
int main(){
    int a[1000000],b[1000000],i,j;
    for(i=0;i<200;i++){
        cin>>a[i]>>b[i];
        if(a[i]+b[i]<=0){
            break;
        }
        if(a[i]+b[i]<10){
            cout<<"1"<<endl;
        }
        else if(a[i]+b[i]<100){
            cout<<"2"<<endl;
        }
        else if(a[i]+b[i]<1000){
            cout<<"3"<<endl;
        }
        else if(a[i]+b[i]<10000){
            cout<<"4"<<endl;
        }
        else if(a[i]+b[i]<100000){
            cout<<"5"<<endl;
        }
        else if(a[i]+b[i]<1000000){
            cout<<"6"<<endl;
        }
        else if(a[i]+b[i]<=1999999){
            cout<<"7"<<endl;
        }
    }
    return 0;
}

C++: #include <iostream>
using namespace std;

int main(){
	double a,b,n=0,c;
	cin>>a;
	cin>>b;
	c=a+b;
	while(c>=1){
		c=c/10;
		n++;
	}
	cout<<n<<endl;
	return 0;
}

C++: #include <iostream>

using namespace std;

int getDigitNumber(int n){
  return n > 0 ? 1 + getDigitNumber(n / 10) : 0;
}

int main(int argc, char const *argv[]) {
  while(true){
    int a,b;
    cin >> a >> b;
    cout << getDigitNumber(a+b) << endl;
  }
  return 0;
}

C++: #include <iostream>
using namespace std;

int main(){ 
    int a,b,cnt,i,j;

    while(cin>>a>>b){
        int add=a+b;
        cnt = 1;
        j = 10; 
        while(1){
            i = add - j;
            if(i>=0)cnt++;
            else break;
            j *= 10;
        }       
        cout << cnt << endl;
    }
    return 0;
}

C++: #include <cstdio>
int main(){
 int d,n,a,b; 
 while(true){
  d=0;
  if (scanf("%d %d",&a,&b)==0) break;
  n=a+b;
  while(n>0) { d++, n/=10 };
  printf("%d\n",d);
  return 0;
};