Hi guys I can't recognize what I've done wrong:

#include <cstdlib>
#include <iostream>
#include <string>
#include <sstream>

using namespace std;

int main(int argc, char *argv[])
{
    int b,c,d,k,n,a[99],TrafficJam=0;
    string line1, line2, line1p, line2p, sk, sn, sa[99];
    size_t pos,pos1[99];
    do
    {
           cout<<"Give first line"<<endl;
           getline (cin,line1);
           pos=line1.find(" ");
           sk=line1.substr(0,pos);
           line1p=line1.substr(pos+1);
           pos=line1p.find(" ");
           sn=line1p.substr(0,pos);
           if ( !(istringstream(sk) >> k) ) k=0;
           if ( !(istringstream(sn) >> n) ) n=0;
    }
    while ( ( sk.size() + sn.size() + 1 ) != line1.size() || k < 1 || k > 100 || n < 1 || n > 100);
    do
    {
          b=0;
          d=-1;
          cout<<"Give second line"<<endl;
          getline (cin, line2);
          line2p=line2;
          for (int i=0;i<n;i++)
          {
              pos1[i]=line2.find(" ");
              sa[i]=line2.substr(0,pos1[i]);
              line2=line2.substr(pos1[i]+1);
              istringstream(sa[i]) >> a[i];
              d+=sa[i].size()+1;
              if (a[i]<0 || a[i] > 100) b++;
          }
    }
    while (b!=0 || d!=line2p.size() );
    for (int i=0;i<n;i++)
    {
        TrafficJam=TrafficJam+a[i]-k;
        if(TrafficJam<0)
        TrafficJam=0;
    }
    cout<<TrafficJam<<endl;
    system("PAUSE");
    return EXIT_SUCCESS;
}

Everything works, but still wrong answer test #1. Can you help? I've tried to find sth for many times, without success.