A stevedore binds four cylindrical steel pipes together with iron wires. The cross-sectional diameter of the steel pipes is 12.5 cm. If the length of the joints of the iron wires is negligible, how long is the iron wire needed to bind 8 turns?
装卸工人把四根圆柱形钢管用铁丝捆扎在一起，钢管的横截面直径是12.5厘米，如果铁丝接头处的长度忽略不计，捆扎8圈，需要多长的铁丝？
<result>716</result>