**Mars Exploration**

### Problem Statement :

A space explorer's ship crashed on Mars! They send a series of SOS messages to Earth for help. Letters in some of the SOS messages are altered by cosmic radiation during transmission. Given the signal received by Earth as a string, s, determine how many letters of the SOS message have been changed by radiation. Example s = 'SOSTOT' The original message was SOSSOS. Two of the message's characters were changed in transit. Function Description Complete the marsExploration function in the editor below. marsExploration has the following parameter(s): string s: the string as received on Earth Returns int: the number of letters changed during transmission Input Format There is one line of input: a single string, s. Constraints 1 <= length of s <= 99 length of s modulo 3 = 0 s will contain only uppercase English letters, ascii[A-Z].

### Solution :

` ````
Solution in C :
In C++ :
#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>
using namespace std;
int main(){
string S;
cin >> S;
long cnt = 0;
for (int i = 0; i < S.size() / 3; i++) {
if (S[3*i+0] != 'S') cnt++;
if (S[3*i+1] != 'O') cnt++;
if (S[3*i+2] != 'S') cnt++;
}
cout << cnt << endl;
}
In Java :
import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
public class Solution {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
String S = in.next();
int numChanged = 0;
for(int i = 0; i < S.length(); i++)
{
if(i % 3 == 1)
{
if(S.charAt(i) != 'O')
{
numChanged++;
}
}
else
{
if(S.charAt(i) != 'S')
{
numChanged++;
}
}
}
System.out.println(numChanged);
}
}
In C :
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>
int main(){
char* S = (char *)malloc(10240 * sizeof(char));
scanf("%s",S);
int i;
int count=0;
for(i=0;S[i]!='\0';i+=3){
if(S[i]!='S'){
count++;
}
if(S[i+1]!='O'){
count++;
}
if(S[i+2]!='S'){
count++;
}
}
printf("%d",count);
return 0;
}
In Python3 :
s = input()
n = "SOS"*(len(s)//3)
cnt = 0
for i in range(len(s)):
if s[i] != n[i]:
cnt += 1
print(cnt)
```

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