This is a back titration question and I'm struggling with it :/ So if you can help me, that would be very appreciated :)

Q. A sample of steel wool was dissolved in excess sulfuric acid. The resulting solution (FeSO4 aq) was then titrated with potassium permanganate. 26.5mL of a 0.18 molL-1 of the permanganate solution was used in a titration with the solution. If the original mass of steel wood was 1.4g. Calculate the percentage of iron in the steel wool. NOTE: Fe2+ ions are oxidised to Fe3+ ions!
Thanks heaps!!