C++ :

#include<iostream>

#include<cmath>

#include<algorithm>

using namespace std;

int main(){

int k,l;

int a[100000],b[100000];

int i=0;

cin>>k;

while(1){

cin>>a[i]>>b[i];

if(a[i]==-1) break;

else i++;

}

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

int tem1,tem2;

for(int q=1;q<i-j;q++){

if(a[q-1]>a[q]){

swap(a[q-1],a[q]); swap(b[q-1],b[q]);

}

}

}

cin>>l;

int c[10000];

c[0]=b[0];

int x=1,y=a[0],z=b[0];

for(int j=1;j<i;j++){

if(a[j]!=y+1){

int p=abs(b[j]-z)/abs(a[j]-y);

int t=1;

while(y!=a[j]){

c[x++]=z-p*t;

t++;

y++;

}

           z=b[j];

}

else{

y=a[j]; z=b[j]; c[x++]=b[j];

}

}

x--; int g=1,h=c[x];

while(c[x]>0){

c[++x]=h-l*g; g++;

}

int d[10000]; int f=0;

for(int j=0;j<x;j++){

d[j]=a[0]++;

}

int e;

for(int j=0;j<x;j++) if(d[j]==k) e=c[j];

int ans1=0,ans2=0;

for(int j=0;j<100;j++){

int max; max=(k-d[0]+j)*e; int s; int flag=0;


for(int r=0;r<x;r++){

s=(d[r]-d[0]+j)*c[r];

if(s>max){

flag=1; break;

}


}

if(flag==0){

ans1=j; break;

}

}

for(int j=-1;j>-100;j--){

int max=(k-d[0]+j)*e; int s; int flag=0;

for(int r=0;r<x;r++){

s=(d[r]-d[0]+j)*c[r];

if(s>max){

flag=1; break;

}

}

if(flag==0){

ans2=j; break;

}

}

if(ans1==ans2&&ans1==0) cout<<"NO SOLUTION"<<endl;

if(ans1==0&&ans2!=0) cout<<ans2<<endl;

if(ans1!=0&&ans2==0) cout<<ans1<<endl;

if(ans1!=0&&ans2!=0&&abs(ans1)>abs(ans2)) cout<<ans2<<endl;

if(ans1!=0&&ans2!=0&&abs(ans1)<abs(ans2)) cout<<ans1<<endl;

return 0;

} 

Pascal :

const
  maxn=50;
  maxm=10000;
var
  d:array[1..maxm] of longint;
  price,sell:array[1..maxn] of longint;
  k1,k2:real;
c,r,t,x,y,n,each,i,j,p,most,m,u1,u2:longint;
begin
  readln(n);
  c:=0;
  repeat
    readln(x,y);
    if (x=-1)and(y=-1) then break;
    inc(c);
    price[c]:=x;
    sell[c]:=y;
  until false;
  readln(m);
  p:=price[1];
  most:=price[c]+sell[c] div m; 
  if (n<p)or(n>most) then
  begin
    writeln('NO SOLUTION');
    halt;
  end;
  for i:=1 to c-1 do
  begin
    each:=(sell[i]-sell[i+1]) div (price[i+1]-price[i]);
    for j:=price[i] to price[i+1]-1 do
      d[j]:=sell[i]-each*(j-price[i]);
  end;    
  for i:=price[c] to most do       d[i]:=sell[c]-m*(i-price[c]);
  k1:=-1e20; k2:=1e20;
  for i:=p to most do   
  begin
    r:=d[n]-d[i];
    t:=i*d[i]-n*d[n]-p*(d[i]-d[n]);
    if (r>0) and (t/r>k1) then
      k1:=t/r;
    if (r<0) and (t/r<k2) then
      k2:=t/r;
  end;
  if k1<-1e19 then u1:=-maxlongint        
  else if (k1>0)and(k1-int(k1)>0) then u1:=trunc(k1)+1 else u1:=trunc(k1);
  if k2>1e19 then u2:=maxlongint
  else if (k2<0)and(int(k2)-k2>0) then u2:=trunc(k2)-1 else u2:=trunc(k2);
 if (u1<0)and(u2>0) then
  begin
    u1:=0;
    u2:=0;
  end;
  if u1>u2 then writeln('NO SOLUTION')
  else if abs(u1)<abs(u2) then writeln(u1)
  else writeln(u2);
  readln;
end.