#include <iostream>
    #include <queue>
    #include <cstring>

    using namespace std;

    class saati
    {
          public:
      int minuti,saat,potezi;
    };

    int main()
    {
          saati od,za;
          cin>>od.saat>>od.minuti;
          cin>>za.saat>>za.minuti;
          od.potezi=0;
          za.potezi=0;
          queue <saati> q;
          bool mat[30][65];
          memset(mat,false,sizeof(mat));
          mat[od.saat+1][od.minuti+1]=true;

          q.push(od);
          while(!q.empty())
          {
                saati tmp=q.front();
                if(tmp.minuti==60)
                {
                      tmp.minuti=0;
                      tmp.saat++;
                }
                if(tmp.minuti==-1)
                {
                      tmp.minuti=59;
                      tmp.saat--;
                }
                if(tmp.saat==24)
                tmp.saat=0;
                if(tmp.saat==-1)
                tmp.saat=23;
                if(tmp.minuti==za.minuti&&tmp.saat==za.saat)
                {
                      cout><<tmp.potezi<<endl;
                      return 0;
                }
                q.pop();
                saati tmp1=tmp;
                tmp1.saat++;
                tmp1.potezi++;
                if(mat[tmp1.saat+1][tmp1.minuti+1]==false)
                q.push(tmp1),
                mat[tmp1.saat+1][tmp1.minuti+1]=true;
                tmp1=tmp;
                tmp1.saat--;
                tmp1.potezi++;
                  if(mat[tmp1.saat+1][tmp1.minuti+1]==false)
                q.push(tmp1),
                mat[tmp1.saat+1][tmp1.minuti+1]=true;
                tmp1=tmp;
                tmp1.minuti++;
                tmp1.potezi++;
                  if(mat[tmp1.saat+1][tmp1.minuti+1]==false)
                q.push(tmp1),
                mat[tmp1.saat+1][tmp1.minuti+1]=true;
                tmp1=tmp;
                tmp1.minuti--;
                tmp1.potezi++;
                  if(mat[tmp1.saat+1][tmp1.minuti+1]==false)
                q.push(tmp1),
                mat[tmp1.saat+1][tmp1.minuti+1]=true;
          }

        return 0;
    }