#include <iostream>

using namespace std;
int matrix[4][9] = {
    { 1, -1,  1,  -1,   5, -1,   7,   7,   5},
    {-1,  2, -1,  -1,  -1,  6,   6,  -1,  -1},
    { 8, -1,  3,   3,  -1, -1,   7,   6,   3},
    { 0,  0,  0,  -2,   0,  0,  -2,  -2,   0}
};

int main() {
    FILE *input = fopen("in.txt","r");
    char currentChar;
    int currentState = 0;
    int validStrCounter = 0;
    int wrongFlag = 0;
    while ( ( currentChar = getc(input) ) != EOF ) {
        switch ( currentChar ) {
            case 'a':
                currentState = matrix[0][currentState];
            break;
            case 'b':
                currentState = matrix[1][currentState];
            break;
            case 'c':
                currentState = matrix[2][currentState];
            break;
            case ' ':
                wrongFlag = 0;
                currentState = matrix[3][currentState];
            break;
        }
        if (currentState == -1) {
            currentState = 0;
            wrongFlag = 1;
        }
        if (currentState == -2) {
            if (wrongFlag != 1)
                validStrCounter++;
            currentState = 0;
        }
    }
    cout << "Number of valid strings = " << validStrCounter << endl;
    fclose(input);
    return 0;
}