type port=record
                x,y:longint;
                end;
var n,m,k,i,j,nr,t:longint;
    v,x:array[1..100100] of port;

begin
assign(input,'stergeri.in');reset(input);
assign(output,'stergeri.out');rewrite(output);
readln(n,m,k);
for i:=1 to m do
        readln(v[i].x,v[i].y);
for i:=1 to m do
        if v[i].x<=k then
                nr:=i;
t:=k;
m:=nr;
repeat
        begin
        k:=t;
        nr:=0;
        for i:=1 to m do
                begin
                if (k>=v[i].x) then
                        t:=t+v[i].y-v[i].x+1
                else
                        begin
                        inc(nr);
                        x[nr]:=v[i];
                        end;
                end;
        for i:=1 to nr do
                v[i]:=x[i];
        m:=nr;
        end;
until t=k;
writeln(t);
close(input);close(output);
end.