How long would it take for a Boeing 747-400 to take off in these conditions?

If there was a Boeing 747-400, with RB211-524H-T engines. There was no payload (including cargo) on board at all. The only weight on the aircraft was the two pilots (around 350 pounds altogether) and 38,000 pounds of fuel. The weather was completely clear, apart from a headwind of 60 knots (around 69 mph) with gusts of up to 70 knots (around 80 mph). The runway was concrete. The temperature was around 15 degrees celcius (around 59 degrees farenheit). There was no turbulence or clouds what so ever. Visibility was over 20 miles. The runway was at sea level. How long approximatly would it take for that plane to take off in them conditions?