int marsExploration(string s) {
   int result = 0;
    string base = "SOS";
    for(int i = 0; i < s.size(); i++) if(s[i] != base[i%3]) result++;
    return result;
}

    count=0
    word="SOS"
    for i in re.findall('...',s):
        if i==word:
            continue
        else:
            if i[0] != word[0]:
                count += 1
            if i[1] != word[1]:
                count += 1
            if i[2] != word[2]:
                count += 1
    return count

def marsExploration(s):
    # Write your code here
    count = 0
    i = 0
    while i < len(s):
        if s[i] != "S":
            count +=1
        if s[i+1] != "O":
            count +=1
        if s[i+2] != "S":
            count +=1
        i += 3
    return count