double sum;
double average;

for(int i =0;i<12;i++)
{

for(int j =0;j<12;j++)
{
    if(j<i&&i+j<11)
  sum += a[i][j];
}

}

if(c=='S') {
    printf("%.1lf",sum);
}else if(c=='M'){
    printf("%.1lf",sum/30);
}

//j<i&&i+j<11